RESOLUTION 1 1). Go to Start Menu and on the list of all available programs, start Microsoft SQL Server [version]|SQL Server [version] Configuration Manager;
2). Once you've opened the SQL Server Configuration Manager on your destination SQL Server environment, go to SQL Server Network Configuration | Protocols for MSSQLSERVER:
3). Open the Protocols settings and make sure that TCP/IP and Named Pipes Protocols are enabled:
4). Dynamically determined TCP/IP ports and Named Pipes are now enabled and opened for communication with your destination SQL server (as shown in the ODBC Connection set up):
5). Using either connection type should work, the error is resolved and you should be able to proceed with System DSN configuration:
RESOLUTION 2 Typically SQL Server uses TCP port 1433, which may be blocked by a firewall. There may be other ports that need to be opened, depending on how SQL Server is configured. For more information see
https://docs.microsoft.com/en-us/sql/sql-server/install/configure-the-windows-firewall-to-allow-sql-server-access?view=sql-server-2017 If the correct ports have been opened in the firewall but there is still connection issue, then turn off the firewall or configure the firewall to "allow all traffic". Then test the DSN connection again to see if it is successful. If the connection is successful, then the firewall is blocking a necessary port/protocol to connect to SQL Server. If the DSN connection fails after opening the firewall, the firewall is not the cause of the connection issue.
If the firewall is the issue, we can turn on logging for dropped ports. See
https://www.howtogeek.com/220204/how-to-track-firewall-activity-with-the-windows-firewall-log/